The DevWallah API Client is a full-featured HTTP client that runs entirely in your browser. There's nothing to install, no accounts to create, and — crucially — your credentials never leave your machine. In this guide we'll walk through every major feature so you can use it as a daily Postman replacement.
Getting Started: Your First Request
Open the API Client from the Tools menu. You'll land on a fresh tab pre-loaded with a GET request. Type any URL into the address bar and press Send or hit Ctrl+Enter. The response body, headers, and timing information appear in the panel below.
Supported HTTP Methods
- 01GET — retrieve resources
- 02POST — create / submit data
- 03PUT — full replacement update
- 04PATCH — partial update
- 05DELETE — remove a resource
Working with Environment Variables
Hardcoding base URLs or API keys into individual requests doesn't scale. The DevWallah API Client supports named environments where you define key–value pairs once and reference them everywhere via the {{variable_name}} notation.
Create a "Development" and a "Production" environment for the same service. Swap between them with a single click in the top-right environment selector and every {{baseUrl}} in your tabs updates automatically.
# Example variables in "Development" environment
baseUrl = http://localhost:3000
apiKey = dev-key-abc123
userId = 42
# Used in a request URL like:
GET {{baseUrl}}/users/{{userId}}Authentication Modes
The Auth tab next to Headers exposes four authentication strategies. Each mode injects the correct credentials automatically so you don't manage raw header strings.
Bearer Token
Paste your JWT or opaque token into the token field. The client prepends "Bearer " and sets the Authorization header on every request in the active tab. You can also reference an environment variable: {{accessToken}}.
API Key
Choose to inject your key as a header (e.g. X-API-Key) or as a query parameter. Both locations are supported and the key name is fully configurable.
Basic Auth
Enter a username and password. The client Base64-encodes "username:password" and sets the Authorization: Basic … header automatically.
Pre-Request & Test Scripts
Need to generate a timestamp, sign a payload, or assert that a response contains a specific field? The Scripts tab provides a lightweight JavaScript sandbox. Use the pm object to access request/response data.
// Pre-request script — set a dynamic timestamp header
pm.request.addHeader("X-Timestamp", new Date().toISOString());
// --- separator: this runs AFTER the response arrives ---
// Test script — assert status and shape
pm.test("Status is 200", () => {
pm.expect(pm.response.status).to.equal(200);
});
pm.test("Response has data array", () => {
const json = pm.response.json();
pm.expect(json.data).to.be.an("array");
});Code Generation
Click the </> Generate Code button in the toolbar and the client renders the current request as production-ready code in four languages: cURL, JavaScript (Fetch), JavaScript (Axios), and Python (requests). Copy it straight into your codebase.
Importing cURL Commands
Got a cURL snippet from Slack, Stack Overflow, or a vendor's docs? Click Import cURL and paste it. The client parses the command and populates all fields — method, URL, headers, and body — into a new tab instantly.
The API Client stores all tabs and history in localStorage. Your work persists across browser refreshes, but is scoped to the current browser. Use Export Config to back up your collections.
Request History
Every successful request is logged in the History panel on the right. Click any entry to restore the full request into a new tab. Useful for replaying previous API calls during debugging sessions without re-typing parameters.